The Yakovlev Yak-40 (Russian: Як-40), NATO reporting name: Codling) is a small, three-engined airliner. It is the world's first commuter trijet. Maiden flight was made in 1966, and production took place from 1967 to 1981. Introduced in September 1968, the Yak-40 was exported since 1970.

By the early 1960s, the Soviet state airline Aeroflot's international and internal trunk routes were flown by jet or turboprop powered airliners but their local services, many of which operated from grass airfields, were operated by obsolete piston engined aircraft such as the Ilyushin Il-12, Il-14 and Lisunov Li-2.[1] Aeroflot wanted to replace these elderly airliners with a turbine-powered aircraft, with the Yakovlev design bureau being assigned to design the new airliner. High speed was not required, but it would have to operate safely and reliably out of poorly equipped airports with short (less than 700 m, (2,300 ft)) unpaved runways in poor weather.[2]

Yakovlev studied both turboprop and jet-powered designs to meet the requirement, including Vertical Take-Off and Landing (VTOL) designs with lift jets in the fuselage or in wing-mounted pods, but eventually they settled on a straight-winged tri-jet carrying 20 to 25 passengers. Engines were to be the new AI-25turbofan being developed by Ivchenko at Zaporozhye in Ukraine.[3]

The Yak-40 is a low-winged cantilevermonoplane with unswept wings, a large T-tail and a retractable tricycle landing gear. The passenger cabin is ahead of the wing, with the short rear fuselage carrying the three turbofan engines, with two engines mounted on short pylons on the side of the fuselage and a third engine in the rear fuselage, with air fed from a dorsal air-intake by an "S-duct", as is an auxiliary power unit, fitted to allow engine start-up without ground support on primitive airfields.[4][5] The three AI-25 engines are two-shaft engines rated at 14.7 kN (3,300 lbf). The engines have no jetpipes, and initially no thrust reversers.[6][7]

The pressurized fuselage has a diameter of 2.4 metres (94 in). Pilot and co-pilot sit side-by-side in the aircraft's flight deck, while the passenger cabin has a standard layout seating 24 to 27 passengers three-abreast, although 32 passengers can be carried by switching to four-abreast seating. Passengers enter the aircraft via a set of ventral airstairs in the rear fuselage.[7][8]

The wing is fitted with large trailing-edge slotted flaps, but has no other high-lift devices, relying on the aircraft's low wing loading to give the required short-field take-off and landing performance. The wings join at the aircraft centerline, with the main spar running from wingtip to wingtip The wings house integral fuel tanks with a capacity of 3,800 litres (1,000 US gal; 840 imp gal). The aircraft has a large fin, which is swept back at an angle of 50 degrees to move the tailplane rearwards to compensate for the short rear fuselage. The horizontal tailplane itself is unswept.[5][9]

The first of five prototypes made its maiden flight on 21 October 1966,[7] with production being launched at the Saratov Aviation Plant in 1967 and Soviet type certification granted in 1968.[5] The type carried out its first passenger service for Aeroflot on 30 September 1968.[9] In the 1972 version, a tailspin was removed. In 1974, new version was introduced, with non-stop flight distance increased. Also, the forward door on the right side of the fuselage changed its place – it was located together with the sixth window.

In 1975, the last upgrade of Yak-40 took place – the number of cabin windows on the right side changed from nine to eight.

By the time production ended in November 1981, the factory at Saratov had produced 1,011 or 1,013 aircraft. By 1993 Yak-40s operated by Aeroflot had carried 354 million passengers.[11] As well as being the backbone of Aeroflot's local operations, flying to 276 domestic destinations in 1980, the Yak-40 was also an export success. More than this, Yak-40 became the first Russian/Soviet aircraft getting flying certificates of Italy and West Germany. It was demonstrated in 75 countries of the world, including the USA, where orders on Yak-40 were made.

As of August 2013 a total of 45 out of 1011 Yakovlev Yak-40 aircraft remain in service. The airworthiness of several Yak-40 of smaller Russian and Central Asian charter airlines is uncertain, as is the whereabouts of one Air Libya Tibesti aircraft after the civil war. Most aircraft in service today have been reconfigured for VIP-charter services, with fewer than ten remaining in scheduled passenger service. Known operators are:[12]

On May 4, 1972, Aeroflot Flight 608, a Yak-40 (CCCP-87778), crashed while on approach to Bratsk Airport after a loss of control caused by windshear, killing all 18 on board.[18]

On February 28, 1973, Aeroflot Flight X-167, a Yak-40 (CCCP-87602), fell back onto the runway at Semipalatinsk Airport during takeoff due to crew error, killing all 32 on board.[19][20]

On May 23, 1974, Aeroflot Flight N-166, a Yak-40 (CCCP-87579), crashed near Kiev due to possible crew incapacitation, killing all 29 on board.[21]

On July 15, 1975, Aeroflot Flight E-15, a Yak-40 (CCCP-87415) struck Mount Mtirala, Caucasus Mountains, during a go-around at Chorokh Airport in poor weather, killing all 41 on board.[22]

On August 15, 1975, Aeroflot Flight A-53, a Yak-40 (CCCP-87323), entered a downdraft and nearly stalled and subsequently crashed on approach to Krasnovodsk Airport due to pilot error and unfavourable weather conditions, killing 23 of 28 on board in Turkmenistan's worst-ever accident.[23][24]

On October 22, 1975, an Aeroflot Yak-40 (CCCP-87458) crashed near Novgorod Airport. Visibility was poor at Novgorod due to fog, but this was not forecast to the crew. A straight-in approach was attempted, but the aircraft went off course after passing the outer marker. The descent continued until the landing gear and wing struck a building and later crashed into an apartment building and a car, killing all six on board and five on the ground.[25]

On September 9, 1976, Aeroflot Flight 31, a Yak-40 (CCCP-87772) from Rostov Airport to Kerch Airport, collided in mid-air with Aeroflot Flight 7957, an Antonov An-24 (CCCP-46518), over the Black Sea 37 km (23 mi) off Anapa due to violation of separation rules, the error of both aircraft crews and probably ground ATC. All 18 occupants of the Yak-40 and 46 people on board the An-24 died.[26]

On October 7, 1978, Aeroflot Flight 1080, a Yak-40 (CCCP-87437), crashed on climbout from Koltsovo Airport following engine failure caused by icing, killing all 38 on board.[27][28]

On June 12, 1980, Aeroflot Flight W-88, a Yak-40 (CCCP-87689), struck the slope of a mountain 44 km (27 mi) northwest of Dushanbe Airport due to navigational errors by the crew while attempting to avoid bad weather, killing all 29 on board.[30][31]

On September 18, 1981, Aeroflot Flight B-652, a Yak-40 (CCCP-87455) from Irkutsk Airport to Ilimskiy Airport, collided in mid-air with a Mi-8 helicopter (CCCP-22268) on a training flight while approaching its destination airport. The supposed site of the collision occurred in the clouds. All 33 on board the Yak-40 and seven occupants of the Mi-8 were killed, making it the third deadliest Yak-40 incident at the time.[32][33]

On January 24, 1988, Aeroflot Flight 29674, a Yak-40 (CCCP-87549), experienced failure of number 1 and 3 engines during take-off from Nizhnevartovsk Airport. Engine number 2 also experienced some problems, but recovered while engines one and three eventually failed. The plane stalled, crashed and broke up, killing 27 of 31 on board. Cause was possible crew error.[34][35]

On August 2, 1988, at Sofia Airport, a Hemus Air Yak-40 LZ-DOK crashed on take-off. All civil traffic had been halted minutes before because of the departure of the Bulgarian leader Todor Zhivkov's Tupolev Tu-154. After the delay, air traffic control cleared LZ-DOK for take-off to Varna, asking the crew to expedite their departure. Trying to leave in a hurry, the crew did not set the trim correctly and began their take-off run from the middle of the 3000 m runaway. The aircraft failed to become airborne, overran the runway into a ravine and caught fire, killing 29 of 37 on board.[citation needed]

On August 28, 1993, a Tajik Air Yak-40 (87995) operating a non-scheduled flight that was grossly overloaded with 81 passengers and five crew members overran the runway on takeoff at Khorog Airport and crashed into the Panj River. The crew were killed and only four passengers survived. The crew may have been forced to overload the aircraft. This is the worst accident involving a Yak-40 as well as the worst-ever accident in Tajikistan.

On February 25, 1994, an Expresso Aéreo plane (OB-1559), piloted by two Russians and one Peruvian,[38] struck Mount Carpish six minutes after leaving Tingo María, Peru for Lima. The 31 occupants were killed.[39]

On September 26, 1994, a Cheremshanka Airlines flight from Krasnoyarsk Airport, Russia to Tura was unable to land at Tura because of bad weather so was diverted to Vanavara. It ran out of fuel due to crew and ATC errors and crashed while attempting an emergency landing on a river, 41 km (25 mi) from Vanavara. All 28 passengers and crew were killed.[40]

On November 5, 1994, another Peruvian aircraft (OB-1569) belonging to the Amazonic regional airline Servicios Aéreos Amazónicos, that was serving the Trujillo-Saposoa-Juanjuí-Tocache-Lima schedule, crashed into the Saposoa River after overrunning the airstrip from the town of the same name. The aircraft either crashed due to heavy rain reported at the time, due to a pedestrian accidentally crossing into the runway or due to both. From the 31 occupants, 26 passengers and 5 crew, 5 passengers and 1 crewmen died.[41][42][43]

On 19 February 1997, a Semeyavia Yakovlev Yak-40 overshot the runway on landing at Semey Airport, Kazakhstan following a scheduled domestic passenger flight. There were no fatalities among the 14 passengers and four crew members on board, but the aircraft was damaged beyond repair.[44]

On May 15, 1997, an Azerbaijan Airlines Yak-40 (4K-87504) crashed near Gyandzha Airport during a training flight, killing all six on board. Stray small-arms fire from Azerbaijani soldiers on the ground struck an oxygen cylinder on the Yak-40, starting a fire. Control was lost and the aircraft crashed.[45]

On January 13, 2004, Uzbekistan Airways Flight 1154, a Yak-40 (UK-87985) from Termez Airport to Tashkent International Airport carrying 37 passengers and crew, crashed; the crew failed to descend for approach on time. Finding the runway too short to land, a go-around was attempted but failed. The plane touched down beyond the end of the runway and the left wing struck a concrete building, with the subsequent crash and fire killing all on board.[48]